It is necessary to use your low beams any time you are:

1. On a lighted street.
2. On a freeway.
3. In fog. ✓

Answer: C. In fog.

You need to use low beams when you are driving in fog.

Why this is the answer

The handbook's fog section tells you to slow down and switch on low beams if you have to drive in thick fog or smoke. It explains that high beams reflect back and cause glare, so low beams are the setting that helps you see without that bounce-back. It also says not to rely on parking lights or fog lights alone. Another section says that when fog makes you use your wipers, you must turn on low beams. Those statements point directly to fog as the condition requiring low beams.

Why the other answers are wrong

• A. On a lighted street. — A lighted street does not by itself make low beams necessary; the handbook lists dark conditions and adverse weather, not street lighting, as reasons to use headlights.
• B. On a freeway. — Being on a freeway is not a listed reason to use low beams; the handbook ties low beams to things like oncoming or followed traffic and weather conditions.

Remember it

In fog, think low: low beams help you see, while high beams bounce glare back at you.